Double tank water gun



FIG. 1 is a front elevational view of a double tank water gun showing our new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a left side elevational view thereof with the right side elevational view being a mirror image thereof;

FIG. 4 is a top plan view thereof; and,

FIG. 5 is a bottom plan view thereof. 

The ornamental design for a double tank water gun, as shown and described. 